Hermetic lead wires used in refrigeration systems are exposed directly to the refrigerant fluid such as liquid and/or gaseous freon. The motors in the system usually vibrate and cause the lead wires to also vibrate. Therefore, it is important that the lead wires be capable of withstanding the vibration and also t withstand deterioration from the refrigerant fluid as well as various compressor motor oils.
The conventional hermetic lead wire which is generally used is formed with a multi-stranded conductor for conducting the electricity and has multi-layered insulation.
The multi-layered insulation generally has a first polyester fiber braid cover over the multi-stranded conductor. The polyester fiber braid is wrapped with polyester tape. The outer layer is a braided polyester fiber sheath.
Our U.S. Pat. No. 4,045,611 provides a hermetic lead wire which eliminated the first inner polyester fiber sleeve of the conventional hermetic lead wire. Our patent utilized for the inner layer a thin foil-like layer of non-woven polyester fibers.
While the conventional hermetic lead wires and the improved lead wire of our U.S. Pat. No. 4,045,611 are generally satisfactory, the braiding process is a relatively slow process. Also, it is difficult to maintain quality control due to undetected tape folds. Loose or tight polyester fiber braids cause customer stripping problems and also tend to provide a relatively large amount of scrap material.